package thinkingInJava.containers.Test_;
// page 509 对比各种 Map 性能
//: containers/MapPerformance.java
//Demonstrates performance differences in Maps.
//{Args: 100 5000} Small to keep build testing short
import java.util.*;

public class MapPerformance {
static List<Test<Map<Integer,Integer>>> tests =
 new ArrayList<Test<Map<Integer,Integer>>>();
static {
 tests.add(new Test<Map<Integer,Integer>>("put") {
   int test(Map<Integer,Integer> map, TestParam tp) {
     int loops = tp.loops;
     int size = tp.size;
     for(int i = 0; i < loops; i++) {
       map.clear();
       for(int j = 0; j < size; j++)
         map.put(j, j);
     }
     return loops * size;
   }
 });
 tests.add(new Test<Map<Integer,Integer>>("get") {
   int test(Map<Integer,Integer> map, TestParam tp) {
     int loops = tp.loops;
     int span = tp.size * 2;
     for(int i = 0; i < loops; i++)
       for(int j = 0; j < span; j++)
         map.get(j);
     return loops * span;
   }
 });
 tests.add(new Test<Map<Integer,Integer>>("iterate") {
   int test(Map<Integer,Integer> map, TestParam tp) {
     int loops = tp.loops * 10;
     for(int i = 0; i < loops; i ++) {
       Iterator it = map.entrySet().iterator();
       while(it.hasNext())
         it.next();
     }
     return loops * map.size();
   }
 });
}
public static void main(String[] args) {
 if(args.length > 0)
   Tester.defaultParams = TestParam.array(args);
 Tester.run(new TreeMap<Integer,Integer>(), tests);
 Tester.run(new HashMap<Integer,Integer>(), tests);
 Tester.run(new LinkedHashMap<Integer,Integer>(),tests);
 Tester.run(
   new IdentityHashMap<Integer,Integer>(), tests);
 Tester.run(new WeakHashMap<Integer,Integer>(), tests);
 Tester.run(new Hashtable<Integer,Integer>(), tests);
}
} /* Output: (Sample)
---------- TreeMap ----------
size     put     get iterate
10     748     168     100
100     506     264      76
1000     771     450      78
10000    2962     561      83
---------- HashMap ----------
size     put     get iterate
10     281      76      93
100     179      70      73
1000     267     102      72
10000    1305     265      97
------- LinkedHashMap -------
size     put     get iterate
10     354     100      72
100     273      89      50
1000     385     222      56
10000    2787     341      56
------ IdentityHashMap ------
size     put     get iterate
10     290     144     101
100     204     287     132
1000     508     336      77
10000     767     266      56
-------- WeakHashMap --------
size     put     get iterate
10     484     146     151
100     292     126     117
1000     411     136     152
10000    2165     138     555
--------- Hashtable ---------
size     put     get iterate
10     264     113     113
100     181     105      76
1000     260     201      80
10000    1245     134      77
*///:~
